Switch unit with integral contact and actuator structure



Nov. 15, 1966' A. H. DRAIN 3,286,049

SWITCH UNIT WITH INTEGRAL CONTACT AND ACTUATOR STRUCTURE Filed Aug. 23, 1965 2 Sheets-Sheet l INVENTOR Alfred H. Druln A. H. DRAIN Nov. 15, 1966 SWITCH UNIT WITH INTEGRAL CONTACT AND ACTUATOR STRUCTURE 2 sheetswsheet 2 Filed Aug. 23, 1965 INVENTOR Alfred H. Drain United States Patent 3,286,049 SWITCH UNIT WITH INTEGRAL CONTACT AND ACTUATOR STRUCTURE Alfred H. Drain, Richland Township, Allegheny County, Pa., assignor to Heppenstall Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 23, 1965, Ser. No. 481,616 13 Claims. (Cl. 200-16) The present invention relates to wiring devices of the multiple contact variety and more especially to wiring devices of the character described which are adapted for cam operation or the like.

Previous wiring devices for use with cam operation have usually taken the form of a micro-switch or the like having a single pair of electrical contacts. Therefore, for multiple circuit operation, two or more such microswit-ches are required. Moreover, the cam follower such as a cam roller or the like usually associated with such switches, can only be disposed in a given directional location relative to the cam for satisfactory operation. Thus, if the conventional cam follower is canted or rotated relative to the cam surface, the switch mechanism either fails to operate or undue switch contact and cam follower wear are encountered, which eventually results in faulty switch operation. In those applications where indicator lamps or other alarm indicia are intended to be simultaneously operated with the load devices to be energized by the cam operated switch, it is necessary to add an additional relay operated contact to the relay usually energized by the micro-switch to apply potential to the indicator lamp. This arrangement introduces a time delay in the indicator lamp operation, which can be critical in certain applications, as in equipment programming circuits, and the like.

In other switch applications, particularly with relation to micro-switches, the switch contacts and associated structures are not capable of carrying sufficient current loads as required in certain applications, without encountering severe damage to the switch contacts from arcing. Moreover, the manner in which the contacts are closed, and the relatively short closure distances in many switch mechanisms fail to provide sufficient wiping action to maintain the contacts in a clean condition.

These problems are solved by my invention, wherein I provide switch means having a tapered or conical cam follower of the like which can be disposed to engage the cam in a variety of angular positions thereto, and in addition having a relatively large contact member movably mounted in the switch means for engaging a plurality of stationary contacts to provide make and break contact with the contact member and with one another through the contact member, which is of a relatively large currentcarrying capacity. The contact member is so shaped and mounted upon the switch plunger or cam follower mechanism so that upon make and break engagement with the stationary contacts, wiping or cleaning action is obtained. In my invention, a supply potential can be applied directly to the movable contact member, which can be electrically insulated from the cam follower so that all of the stationary contacts can be coupled respectively to load circuits associated with the switch means. On the other hand and in other applications, it is preferable to connect one of the stationary contacts to a source of potential with the remainder of the stationary contacts being coupled to load circuits as noted previously. In either arrangement, the switch means of my invention are arranged so that the movable contact member engages or disengages the stationary contacts simultaneously so as to permit simultaneous actuation of a number of load circuits.

' Patented Nov. 15, 1956 "ice These and other details, objects and advantages of the invention, will become apparent as the following description of certain presently preferred embodiments thereof proceeds.

In the accompanying drawings, I have shown certain presently preferred embodiments of the invention where- FIGURE 1 is a front elevational view, partially sectioned, of one form of switch means arranged in accordance with the invention;

FIGURE 2 is a top plan view of the switch means of FIGURE 1; i 7

FIGURE 3- is a side elevational view of the switch means of FIGURES 1 and 2;

FIGURE 4 is a side elevational view of another form of switch means arranged in accordance with the invention;

FIGURE 5 is a. front elevational view partially in section and partially broken away of still another form of switch means arranged in accordance with the invention;

FIGURE 6 is a side elevational view of the switch means of FIGURE 5;

FIGURE 7 is a top plan view of the switch means of FIGURES 5 and 6;

FIGURE 8 is a side elevational view of yet another form of switch means arranged in accordance with the invention; and,

FIGURE 9 is a front elevational view partially sectioned, of still another form of switch means of the invention. 1

Referring now to FIGURES 1-3 of the drawings, an exemplary form of switching means is illustrated therein for use in this arrangement, with a cam actuator or the like. In the latter switch arrangement a channeled bracket having a base portion 102 and a smaller overhead portion 104 is provided. In the upper or overhead portion 104 are mounted a plurality of stationary contacts 106, preferably with three equally spaced such contacts being employed in this example of the invention. It is contemplated, of course, that a greater or lesser number of fixed contacts can be employed depending upon the application of the invention. However, as pointed out more fully below, in certain applications of the invention the self-centering and self-cleaning actions of the switch mechanism, as well as simultaneity of contact engagement are enhanced when three contacts 106 are utilized, particularly when uniformly and angularly spaced about the axis of the plunger 112 and contact 108, which will now be described. The contacts 106 desirably are closely spaced for simultaneous contact therewith by a relatively large contact disc 108, which can be positioned for movement upwardly against the action of a relatively light, downwardly biasing spring 110. The spring 110 surrounds a flanged plunger 112 threadedly secured at its upper end to the contact disc 108 and at its lower end to a cam follower 114 fabricated from nylon or other suitable bearing material.

A conical or spheroidal shape of the follower 114 permits operation of the switch means in a variety of directional dispositions relative to the associated cam surface as opposed to a follower wheel and plunger, which can be operated through one path only.

Referring once again to the contact disc 108, it will be seen from FIGURES 1 and 2 that the contacting surface thereof forms, in this example, a frustoconical section 109. The conical surface 109 is self-centering on the three contacts 106, which in this example, are spaced at about the axis of the contact disc 108 and the plunger 112. The conical surface 109 in addition provides a wiping, self-cleaning action upon the contacts 106 and the juxtaposed surfaces of the contact disc 108, since it is very unlikely that normal manufacturing tolerances will permit the contacts 106 and the disc 108 to be perfectly centered. In this connection, it may also be pointed out any dirt and other contaminants tend to roll or slide off a contacting surface of this configuration. Further wiping or self-cleaning action upon the contacts 106 and disc 108 occurs because the contact disc 108 is free to rotate with its plunger 112. This rotation, due to vibration in the equipment and other environmental factors, is further stimulated by recurrent operation of the switch means, since the plunger 112 and disc 108 will seldom, if ever, be mounted precisely perpendicular to the cam surface of the programming element 10. This condition will result in another rotational force being exerted upon the contact disc-108 to ensure that new disc surface 109 is constantly presented to the contacts 106.

Alternatively, a spheroidalsurface 116 (FIGURE 4) can 'be imparted to the contact side of the disc -8. Either a spherical or conicalsurface 109 allows more freedom of fit of the plunger-112m the bracket guide opening 113 therefor. 'Cant ing or tilting of the plunger 112 within the limits imposed by the guide opening 113 will, therefore, have no effect upon the circuit-closing efficacy of the switch means and thus will not reduce its current carrying capacity. Moreover, a sufficient guide opening clearance will ensure simultaneity of engagement of the movable contact 108 with the stationary contacts 106, particularly when three contacts 106 are used, even if the plane established by the contact points thereof is not precisely perpendicular to the path of plunger movement, either through unequal wear or as a result of initial manufacturing tolerancesl It maybe noted here that the current capacity of the switch will be relatively large due to the rather massive construction of the contact disc 108 and contacts 106, which need not be-rnounted on leaf springs, or the like, of relatively high electrical resistance. I

If desired, the plunger 112 can be booted (not shown) and the switch mechanism encapsulated (not shown) in communication with the plunger boot for dustproof or oiltight applications. The switchenclosure can 'be evacuated or filled with an inert'gas for greater current carrying capacity. Environment modifying agents, such as getters, can be inserted into the enclosure to inhibit corrosion or extend contact life or suppress arcing, etc.

The use of three contacts 106 not only provides selfcentering action but is also conveniently suitable as a true check or indication of switch actuation. Time lags are often important in this regard and timing would be exact in this case. One contact 106 is connected in a power source. Another contact 106 is connected in the conventional manner to a relay or solenoid (not shown) or other device to be actuated. The third contact is connected to an indicating device (not shown). The normal practice of operating the indicating device from a contact on the actuated relay not only removes the availability of that relay contact for other service but also introduces the relay operating time as an undesirable time lag, which produces erroneous indications.

The component parts of the switch means of the invention are few in number and are readily fabricated for interchangeability and easy replacement. Integral components, such as the riveted contact and leaf spring assemblies of conventional switches, which assemblies cannot be replaced conveniently, are avoided.

Referring again to FIGURE 4 of the drawings, Wherin reference characters with primed accents denote similar components, another modification of the switch means is shown wherein a ball follower 118 is rotatably retained in the follower 120 of the plunger 112'. The ball 118 is retained in the follower 120, in a convention-a1 manner, as by the provision of a retaining lip 122 in the extremity of the follower 120.

The use of the ball follower 118-120 also permits operation of the switch means in a variety of angular dispositions thereof relative to the associated cam surface or the like.

Referring now to FIGURES 5 to 7 of the drawings, wherein reference characters with prime accents denote similar components, an arrangement of my switch means is shown together with means incorporated therein for providing overtravel cushioning. In this example, the switch housing represented by the channeled bracket 100 of FIGURES 1 to 3 is provided in bipartite form including a base plate 122 and an inverted, as viewed in FIGURES 5 and 6 of the drawings, channel bracket 124. Theg stationary contacts 106 are mounted upon the channel member 124, for example in the manner described above in connection with FIGURES 1 to 3.

In order to accommodate overtravel of the contract disc 108', the channel bracket 124 is spring-loaded or other wise biased into engagement of its depending side portions 126 with the adjacent upper surfaces of the base plate 122. One arrangement for accomplishing this includes use of normally disposed slideway means mounted on the base plate 122 and including in this example, a number of stripper bolts 12-8, with four such bolts being employed in this example as better shown in FIGURE 7. The stripper .bolts 128 are threadedly engaged at their lower threaded portions in suitably tapped apertures 130 therefor in the plate 122. The stripper bolts are staked :at their lower threaded extensions as denoted by reference character 132, and the housing portion or channeled bracket 124 is slida-b ly mounted on the unthreaded portions of the bolts 128 which respectively pass through associated apertures 134 in the bracket.

When secured as aforesaid, the stripper bolts are of such length as to project upwardly of the top surface 136 of the channel bracket 124. A like number of biasing springs 128 are respectively mounted upon the projecting portions of the stripper bolts 128 and are compressed between heads 140 thereof and the adjacent surface of the channel bracket 124. With this arrangement, displacement of the contact disc 108 upwardly, as viewed in FIGURES 5 and .6, through a greater distance than that normally existing between the contact disc 10S and the stationary contacts 106 will cause the normally stationary contacts 106' to be moved upwardly together withthe spring-loaded channel bracket 124, on which the contacts 106 are mounted.

Referring now to FIGURE 8 of the drawings, a double-throw-multiple-pole switch means, is arranged in accordance with the invention. In FIGURE 8, reference characters with primed accents denote similar components of FIGURES 1 to 3 or of FIGURES 5 to 7, as the case may be. In this form of the invention, a number of normally closed stationary contacts are mounted upon the supporting plate 122 and disposed for engagement with the underside of the contact disc 144, which is mounted upon spring-loaded plunger 112' as described previously in connection with FIGURES 1 to 4 of the drawings. The contact disc 144, therefore, is biased into a norm-aly closed contact position relative to the lower stationary contacts 142. The upper stationary contacts 106' are mounted upon the top surface 136' of channeled bracket 124' as described above with reference to FIGURES 5 to 7 of the drawings. The latter contacts 106, therefore, are onr-mally spaced from the contact disc 144, and constitute the normally open contacts of the switch means.

In this example, three each of the normally closed contacts 142 and of the normally open contacts 106' are utilized, and are preferably arranged in a uniformly spaced array about the axis of the plunger 112 and the contact disc 144. The contact disc 144 desirably is double-faced with the aforementioned conical or spherical surfaces. In this example, as illustrated in FIGURE 8, the opposite faces 146 of the contact disc 144 are spherically contoured. The spring-loaded overtravel means illustrated in FIGURE 8 and described in detail in connection with FIGURES 5 to 7 obviously can be omitted from the arrangement of FIGURE 8 depending on the application of the switch means and the housing structure illustrated in FIGURES 1 to 4 or in FIGURE 9 can be substituted.

With reference now to FIGURE 9 of the drawings where similar reference characters with primed accents refer to similar components of FIGURES 1 to 3, another form of overtravel cushioning means is illustrated in connection with the housing structure illustrated in FIGURES 1 to 3 of the drawings. In the last-mentioned form of the invention, a plunger 148 for the contact disc 108 is provided with a generally hollow or tubular configuration. The plunger 148 is threaded at its upper end into a tapped opening in the underside of the contact disc 108' as denoted by reference character-150. At the lower extremity of the plunger 148 an outwardly turned flange 152 therof serves as a stop for plunger biasing spring 110. In this example, cam follower 154 is biasedly retained within the tubular plunger 148 by means of its upper out-turned flange 156 cooperatively engaging inwardly extending shoulder 158 'of the tubular plunger 148. The cam follower 154 is biased to a cam engaging portion, as shown in FIGURE 9, by means of a compressed coil spring or the =like 160 retained within the plunger 148 between the contact disc 108' and the upper end of the plunger 154. The

eflicient forms of switch means have been disclosed herein.

While I have shown and described certain presently preferred embodiments of the invention it is to be understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims. Moreover, it is to be understood that certain features of the invention can be utilized to advantage without a corresponding use of other features thereof;

I claim:

1. Switch means for use with a cam operator and the like, said switch means including a supporting bracket, a plunger extending through an aperture in said bracket for rectilinear path of movement relative thereto, a cam follower and a generally circular contact disc mounted on said plunger, a planar array of spaced stationary contacts mounted on said bracket and juxtaposed to said disc for make and break contact with said disc upon movement thereof, said aperture being slightly larger than the juxtaposable cross-sectional configuration of said plunger to allow a given amount of misalignment thereof relative to said path, the contacting surface of said disc being uniformly tapered toward and around its circumferential edge to afford wiping of said surface relative to said contacts and centering of said disc and plunger relative to said array of contacts, and biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator.

2. Switch means for use with a cam operator and the like, said switch means including a supporting bracket, a plunger and cam follower mounted on said bracket for rectilinear movement relative thereto, a movable contact mounted on said plunger for movement therewith, a plurality of stationary contacts mounted on said bracket and juxtaposed to said moveable contact for make and break contact therewith upon movement thereof, and biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator, said cam follower terminating in a ball follower member rotatably mounted in the terminus of said follower adjacent the cam operator surface to permit mounting said switch means in a variety of angular dispositions relative to the surface of the cam operator.

3. In a switch means including bipartite support members, a plunger movably mounted on one of said support members, a contact member mounted on said plunger, at least one stationary contact mounted on the other of said support membersv and juxtaposed to said contact member for make and break contact therewith, means for moving said plunger and said contact member to make and break positions of the latter relative to said stationary contact, and means for biasing said support members together so that overtravel of said plunger separates said support members to prevent damage to said switch means.

4. The combination according to claim 1 characterized in that three such stationary contacts are mounted on said supports, said cont-acts being equally and angularly spaced about the longitudinal axis of said plunger.

5. Switch means for use with a cam operator and the like, said switch means including a bipartite suporting housing, a plunger and cam follower mounted on one of said housings parts for rectilinear movement relative thereto, a contact member mounted on said plunger for movement therewith, a plurality of stationary contacts mounted on the otherhousing part and juxtaposed to said contact member for make and break contact therewith upon movement thereof, biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator, and additional biasing means urging said housing parts together so that overtravel of said contactmember engages-said stationary contacts and separates said housing parts.

6. Switch means for use with a cam operator and the like, said switch means including a relatively stationary support, a plunger and cam follower mounted on said stationary support for rectilinear movement relative thereto, a contact member mounted on said plunger for movement therewith, a relatively movable. support, means for biasedly mounting said. movable support on said stationary support, a plurality of stationary contacts mounted on said movable support and juxtaposed to said contact member for make and break contact therewith upon movement thereof, biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator, and means for biasing said stationary support and said movable support together so that overtravel of said contact member when engaged with said contacts separates said supports to prevent damage to said switch means.

7. Switch means for use with a cam operator and the like, said switch means including a supporting bracket, a plunger and cam follower mounted on said bracket for rectilinear movement relative thereto, a contact member mounted on said plunger for movement therewith, a plurality of stationary normally open contacts mounted on said bracket in normally spaced relation to said contact member and juxtaposed thereto for make contact with said contact member upon movement thereof, a number of stationary normally closed contacts mounted on said bracket and normally engaged with said contact member but in break relation therewith upon movement thereof, and biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator and for urging said contact member against said normally closed contacts.

8. The combination according to claim 7 characterized in that said normally open contacts are mounted upon a support movably and biasedly mounted on said bracket so that overtravel of said contact member and plunger engages said contacts to move said support without damage to said switch means.

9. Switch means for use with a cam operator and the like, said switch means including a supporting plate, a plunger and cam follower mounted on said supporting plate for rectilinear movement relative thereto, an inverted channel bracket having its depending sides normally engaging said supporting plate and slidably mounted upon upright slideway means afiixed to said supporting plate, biasing means coupled to said slideway means and to said channel bracket for urging said channeled bracket into engagement with said supporting plate, a contact member mounted on said plunger for movement therewith, a plurality of stationary contacts mounted on said channel bracket and juxtaposed to said contact member for make and break contact with said contact member upon movement thereof, and additional biasing means coupled to said plunger for urging said cam follower against a surface of the cam operator, said first-mentioned biasing means permitting movement of said channel bracket on said slideway means during overtravel of said contact member when engaged with said stationary con tacts.

10. Switch means for use with a cam operator and the like, said switch means including a supporting bracket, a plunger and cam follower mounted on said bracket for rectilinear movement relative thereto, said cam follower being slidably mounted on said plunger for movement generally parallel to said plunger movement, a cont-act member mounted on said plunger for movement therelike, said switch means including a supporting bracket, a plunger mounted on said bracket for generally rectilinear movement relative thereto, a contact member mounted on said plunger for movement therewith, a plurality of stationary contacts mounted on said bracket and juxtaposed to said contact member for make and break contact therewith upon movement thereof, means for slidably mounting a cam follower for movement toward and away from said contact member and generally in the path of said rectilinear movement, biasing means coupled to said plunger and to said bracket for urging said contact member to a normally open contact position thereof relative to said contacts, and additional biasing means coupled to said contact member and to said cam follower for urging said cam follower to a position of engagement with a surface of the cam operator, said additional biasing means being of greater strength than said first-mentioned biasing means so that said cam follower is moved toward said contact member only upon overtravel of Said cam follower and engagement of said contact member with said stationary contacts to prevent dam age to said switch means.

13.- The combination according. to claim 3 wherein slideway means are mounted on one of said support members, the other of said support members is movably mounted on said slideway means, said slideway means greater strength than said first-mentioned biasing means so that said cam follower is moved against said additional biasing means only upon overtravel thereof after engagement of said contact member with said stationary contacts. a

11. The combination according to claim 10 characterized in that said plunger is of generally tubular configuration having an out-turned flange engaging said first-mentioned biasing means in the form of a spring, said cam follower is mounted for sliding movement within said tubular plunger, and said additional biasing means is a compressed coiled spring retained within said plunger and engaging said cam follower to urge the latter against a shouldered stop adjacent the outer opening of said plunger.

12. Switch means for use with a cam operator and the being disposed generally parallel to said plunger, and said biasing means being coupled to said slideway means and to the last-mentioned other support member for biasing said support members together.

References Cited by the Examiner UNITED STATES PATENTS 2,006,690 7/1935 Blake 200-16 X 2,115,069 4/ 1938 Hall 200-166 2,821,580 1/1956 Black 200-16 X 2,892,047 6/ 1959 Smith 200-16 X 2,901,581 8/1959 Russell 200-16 X 3,153,131 10/1964 Gratzmuller 200-166 3,168,635 2/ 1965 Gebhart 200-166 ROBERT K. SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.-

J. R. SCOTT, Assistant Examiner. 

1. SWITCH MEANS FOR USE WITH A CAM OPERATOR AND THE LIKE, SAID SWITCH MEANS INCLUDING A SUPPORTING BRACKET, A PLUNGER EXTENDING THROUGH AN APERTURE IN SAID BRACKET FOR RECTILINEAR PATH OF MOVEMENT RELATIVE THERETO, A CAM FOLLOWER AND A GENERALLY CIRCULAR CONTACT DISC MOUNTED ON SAID PLUNGER, A PLANAR ARRAY OF SPACED STATIONARY CONTACTS MOUNTED ON SAID BRACKET AND JUXTAPOSED TO SAID DISC FOR MAKE AND BREAK CONTACT WITH SAID DISC UPON MOVEMENT THEREOF, SAID APERTURE BEING SLIGHTLY LARGER THAN THE JUXTAPOSED CROSS-SECTIONAL CONFIGURATION OF SAID PLUNGER TO ALLOW A GIVEN AMOUNT OF MISALIGNMENT THEREOF RELATIVE TO SAID PATH, THE CONTACTING SURFACE OF SAID DISC BEING UNIFORMLY TAPERED TOWARD AND AROUND ITS CIRCUMFERENTIAL EDGE TO AFFORD WIPING OF SAID SURFACE RELATIVE TO SAID CONTACTS AND CENTERING OF SAID DISC AND PLUNGER RELATIVE TO SAID ARRAY OF CONTACTS, AND BIASING MEANS COUPLED TO SAID PLUNGER FOR URGING SAID CAM FOLLOWER AGAINST A SURFACE OF THE CAM OPERATOR. 